A friend dropped by last night to have me look over a few cams he was considering for use in a rebuild. One of the cams, from a 1913 engine, had the bearings on it yet. After removing them, it was pretty obvious there was none of the usual babbitt lining in them. It's not that it wore away. The bearing bores were in pretty good shape but just plain cast iron with no babbitt overlay. The cam bearing journals look pretty good too, and not unusually worn for having been run against cast iron.

Is this how early cam bearings were made? Maybe they were aftermarket?

All of the Kubota tractor engines run steel cams in their cast iron block. As long as you have different metals and good lubrication you can go without soft bearing materials. They marinize these engines and call them "Universal Engines" In tractors they are painted blue. When Universal marinizes them they paint them with copper paint.

Perhaps Henry found out that his splash oil system did not do the job and had to add babbitt because of his marginal lubrication system

I pulled my box of cam bearings and took a look. I have about 20 pair. They are a combination of repros I purchased over the years but didn't use for one reason or another, and others I pulled from engines I disassembled and/or restored. I kept the best I had and always banded them together so they could be installed as matched halves. All the center bearings that are not repro are cast iron without babbitt. All the fronts except one had babbitt. That one is an NOS early front bearing that had a Ford tag wired to it when I got it. By early I mean the bearing had the notch for clearing the front lobe. The photo below shows the center bearings and the one cast front bearing.

I pulled my box of cam bearings and took a look. I have about 20 pair. They are a combination of repros I purchased over the years but didn't use for one reason or another, and others I pulled from engines I disassembled and/or restored. I kept the best I had and always banded them together so they could be installed as matched halves. All the center bearings that are not repro are cast iron without babbitt. All the fronts except one had babbitt. That one is an NOS early front bearing that had a Ford tag wired to it when I got it. By early I mean the bearing had the notch for clearing the front lobe. The photo below shows the center bearings and the one cast front bearing.

Wow, thanks for the effort of looking those up. Very interesting indeed. The center bearing I found looked just like yours. The front bearing, though I can't see the outside of yours, seemed somewhat different. Looks like maybe they were a Ford supplied item. Don't know why I never saw one before.

Cam bearings used in '09-'10 used two snap rings each. I have a mid '10 engine that way. The early parts books with the large drawings make it quite clear the difference between early and later bearings. I have never found a cam bearing with out babbitt.